Alexei - see the solution from make GUI slider behave like iOS frame scroller which will tell you how to create a continuous value change listener for the slider. The only thing that ail be missing is how to update the text box which you can do by just modifying the slider1ContValCallback (from the link) as
function slider1ContValCallback(hFigure,eventdata)
% test it out - get the handles object and write the current value
% to the edit box
handles = guidata(hFigure);
sliderValue = get(handles.slider1,'Value');
set(handles.text1,'String',num2str(sliderValue));
The above assumes that text1 is the tag for the text box that you wish to update, and that slider1 is the tag for your slider.
Try it out and see what happens!
